In wireless radio systems, multiple-input and multiple-output (MIMO) systems involve the use of multiple antennas at both a transmitter and receiver to improve communication performance. MIMO uses the multiple antennas to coherently resolve more information than possible using a single antenna. A Distributed Antenna System (DAS) is a network of spatially separated antenna nodes connected to a common source using a transport medium that generally provides wireless service within a geographic area. A DAS will often replace a single antenna radiating at high power level with a group of low-power antennas to cover the same area.
MIMO operations require transporting large amounts of data (e.g., digital samples) to a central processing unit for joint decoding. Traditional implementations of MIMO are generally performed using a single device. Therefore, the scale of MIMO is limited, such that a number of cooperating antennas may only be in the range of 2-4. Traditionally, distributed-MIMO is only a MIMO system with special extended antenna cables for connecting the cooperating antennas to a radio.